Method for the manufacture of cooling parts for a cooling garment

ABSTRACT

Method for the manufacture of cooling parts for a cooling garment comprising the application of an absorbing polymer material to a first layer of a permeable fabric, covering the first layer and the absorbing polymer material with a second layer of a permeable fabric and connecting together the first and the second layer in a connecting pattern, wherein the absorbing polymer material is applied in immobilized form and cooling garment, comprising cooling parts comprising a first layer of fabric and a second layer of fabric, the first and second layer having been connected together in a pattern, the pattern forming pockets, the pockets containing absorbing polymer material, wherein in addition to the absorbing polymer material the pockets further contain a water soluble polymer.

The invention relates to a method for the manufacture of cooling parts for a cooling garment comprising the application of an absorbing polymer material to a first layer of a permeable fabric, covering the first layer and the absorbing polymer material with a second layer of a permeable fabric and connecting together the first and the second layer in a connecting pattern.

Such method is known from US 2007/0225782 A1. The absorbing polymer material is applied as a layer of small particles from a hopper on a moving first layer. A distribution member is used to control the thickness of the layer of material applied.

This method is less suitable for applying absorbing polymer material in a predetermined pattern on the first layer and until the connecting is finished, the absorbing polymer material lying on the first layer is susceptible to undesired displacements due to movements of the first layer which limits easy handling of this layer.

Aim of the invention is to provide a method having more flexibility in handling the first layer with the absorbing polymer material on it and requiring less care when handling said layer.

This aim is achieved in that the absorbing polymer material is applied in immobilizing form.

The absorbing polymer material is considered to be in immobilizing form when after applying the material, the absorbing polymer material is secured on the location it has been applied to, the location corresponding to a pocket where the material is intended to be locked in by the connecting process.

From US 2007/0225782 A it is known to include a separate obstruction member into the pockets in addition to the absorbing polymer. This obstruction member may prevent undesired displacement(s) of the absorbing polymer particles after the pockets have been formed but it will not do so during the handling of the layers. Moreover the present method is less complicated since it can use simple plain layer material and only the absorbing polymer material has to be applied onto the layer and no further material like fibers, glue and the like.

The cooling parts manufactured by the method according to the invention are suitable to compose a device from for cooling (parts of) the human or animal body, in particular a cooling garment.

In a cooling garment composed from cooling parts manufactured according to the invention the absorbing polymer material can absorb a liquid, e.g. water causing it to swell and form a gel containing considerable amounts of the liquid. When the garment is worn evaporation of the absorbed liquid from the gel will have a cooling effect on the body of the wearer. In addition, the garment, after swelling of the absorbing polymer material, may be chilled even to near or even below freezing to provide an extra chilling effect on the body of the wearer of the garment in first instance by the low temperature or melting of the gel and further by the evaporation of the liquid from the gel. The first and the second layer therefore are of a material permitting evaporation. In general not all places of the body covered by the garment will require the same amount of cooling. For that reason it is preferred that the amount of absorbing polymer material present in cooling parts at a certain position of the garment is adapted to the local cooling required.

The absorbing polymer material is locked in pockets, formed by the connecting pattern applied.

As absorbing polymer material polymer materials can be used that are able to form a gel on absorption of considerable amounts of liquid. When water is used as the liquid the gel is called a hydrogel.

A gel is a network of natural or synthetic polymer chains that are insoluble to the absorbed liquid, sometimes found as a colloidal gel in which the liquid is the dispersion medium. Gels are highly absorbent and can contain over 99% liquid. In view of the intended use, viz. on the human body, water is the preferred liquid used. Hydrogels also possess a degree of flexibility very similar to natural tissue, due to their significant water content. Examples of absorbing polymer materials are sodium polyacrylate, acrylate polymers and copolymers with an abundance of hydrophilic groups, polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxymethylcellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and starch grafted copolymer of polyacrylonitrile Natural hydrogel materials include agarose, methylcellulose and hyaluronan. Most of the absorbing polymer materials mentioned above are so-called super absorbent polymers (SAP), also called slush powder, and can absorb and retain extremely large amounts of a liquid relative to their own mass. The total absorbency and swelling capacity are controlled by the type and degree of cross-linking to the polymer. Low density cross-linked SAP generally has a higher absorbent capacity and swell to a larger degree. These types of SAP also have a softer and more cohesive gel formation. High cross-link density polymers exhibit lower absorbent capacity and swell. The gel strength is firmer and can maintain particle shape even under modest pressure. Super absorbent polymers are commercially obtainable as particles ranging from fine powders to granules of several millimetres.

Absorbing polymer material is applied to a first layer of a material permitting evaporation, preferably a permeable fabric. A permeable fabric allows liquid like water and transpiration fluid and evaporated liquid to pass through the fabric. This allows the absorbing polymer material in the garment to form a hydrogel when the garment is immersed in or otherwise exposed to a liquid, in particular water. A wide range of fabric can be used as the first layer depending on further requirements expected from it such as wearing comfort, colour, thickness, flexibility, stretchability, printability and other requirements for the inner or outer layer of a garment.

The permeable fabric of the second layer can be of the same material as the first layer but may also be different to fulfil the requirements as mentioned above. In practice one of the first and second layers will be the inner layer of the garment and the other layer will be the outer layer and these different positions of the layers in practice may impose different requirements.

The absorbing polymer material is applied to the first layer in a predetermined pattern. The amount of absorbing polymer material applied may vary from place to place, e.g. depending on the location on the body where the specific spot of the part to be manufactured is intended to come into contact on wearing. These variations can be differences in thickness of an absorbing polymer material containing layer but also the absorbing polymer material can be applied as distinct piles or drops of absorbing polymer material containing paste on certain spots. Certain areas or strips then may be kept free of absorbing polymer material for reasons set out below.

The first and the second layer are connected together in a connecting pattern. Connecting can be done by known techniques for locally connecting fabrics, in particular along lines of limited width, like gluing, sealing or stitching. When gluing or sealing is applied glue resp. sealing tape will be applied to the first layer in the connecting pattern before it is covered by the second layer. By connecting the first and second layer in a pattern of crossing straight or curved lines pockets are formed, containing a desired amount of absorbing polymer material or enclosing empty spaces. Such empty spaces or empty pockets, as separated spots or as elongated strips, may allow vapor or liquid, e.g. transpiration fluid or vapor, to be transported from a wearer's body through the garment to the environment. Stitching usually allows very narrow connecting lines, in particular having the thickness of the stitching thread as their width. In this aspect stitching allows the empty spaces to be formed in a favorable way when parallel stitching line pairs are applied. Neighboring pairs then form the boundaries of pockets containing absorbing polymer, whereas the area between the two lines forming a pair then form empty spaces. Feasible distances between two lines forming a pair can range preferably from 0.1 to 10 cm, more preferable from 0.2 to 5 cm and most preferable from 0.3 to 3 cm. Applying this way of stitching will result in a flexible garment that combines cooling pockets uniformly covering the body with relatively small uniformly distributed areas for fluid or vapor transport to the environment. Another advantage of applying this way of connecting is that the garment will remain flexible even when the gel in the pockets are frozen. Pockets may have any shape, depending on the connecting pattern applied. Most practical shapes will be squares, diamonds and rectangles or similar shapes having curved sides. Curved sides have the advantage of leveling exerted pressure preventing absorbing polymer material to leak out of the pockets as compared to sharp angles in normal practical shapes of the pockets mentioned above. Pocket areas may range from 1 to 200 cm², preferably from 2 to 100 cm² and more preferable from 3 to 50 cm².

When gluing or sealing is applied empty spaces can also be formed by parallel lines of glue or sealing tape. These lines in general will be broader than stitched lines. In the latter case the useful area, either for cooling or for fluid/vapor transport will be larger than in the former case. Where flexibility is the most important issue also a single line of a broader tape can be applied albeit on the cost of loss of permeability over the area of the tape. Gluing and sealing have the advantage over stitching that no perforation of the layers will be present. Perforations may, on the long run due to wear, cause leakage of absorbing polymer material from the pockets.

In the method according to the invention the absorbing polymer material is applied in immobilizing form.

In a first embodiment the absorbing polymer material is applied as a mixture with a diluent, the mixture having adhesive properties to the first layer. A polyvinyl alcohol-water mixture is a broadly applicable diluent. Also diluted liquid or water soluble glues may be applied. This mixture preferably has a paste-like consistency to prevent flowing or sagging of the absorbing polymer material applied outside the region of the pocket it is intended to be locked in by the connecting process. The adhesive properties attach the applied amount of mixture to the first layer thus disabling it from moving from the location it has been applied to. For dosing the mixture known dosing equipment for paste-like substances can be applied and such equipment is also suitable to dose different amounts at different locations of the first layer, matching the size of the pockets that will be formed in the connecting step at those different locations in the cooling garment. Preferably the diluent comprises water.

In a second embodiment the absorbing polymer material is packed in bags of liquid-, preferably water-, soluble or permeable material, preferably polymer. The size and contents of the bags are adapted to the amount of absorbing polymer material to be contained in the various pockets. It is also feasible to use bags having size and content corresponding to the smallest amount required for any pocket and applying multiple bags when larger amounts of absorbing polymer material are required for other pockets. Although the bags, due to their size and contents, which are larger than those of the individual absorbing polymer material particles, are less susceptible to displacement, it is feasible to make the bags adhesive to the first layer in order to achieve the desired immobilizing effect. This can be done e.g by applying glue to the bags before applying these to the first layer or by wetting these slightly to make them tacky.

In a third embodiment the absorbing polymer material is applied as pieces of a non-woven fleece or sheet consisting of or comprising the absorbing polymer material. A piece of a non-woven fleece or sheet is no larger than equal to and preferably smaller than the size of the pocket it is intended to be comprised in. The fleece or sheet may be given adhesive properties to the first layer in an analogous way as described above for the first and second embodiment.

In all embodiments the first layer and the corresponding second layer may have the shape of the part of the garment it is intended to form, for example front part, back part, sleeve, collar or trouser leg. They may also be larger than said part allowing said part to be cut out of it later.

The use of a liquid—preferably water—soluble adhesive material—preferably a polymer—has the advantage that the material can be rinsed out when the garment is finished, thus having no influence on the use properties of the garment. Preferably the water soluble adhesive material is rinsed out (less than 1 wt % of the starting amount) within 100 activation cycles, more preferably within 10 activation cycles. One activation cycle is defined when the liquid from the fully liquefied absorbing polymer material is evaporated.

To apply the absorbing polymer material in the predetermined pattern on the first layer a feeder system for the absorbing polymer material is used. Feeder systems for powder, granules, pastes or small bags filled with powder or granules are known per se. Preferably the feeder system and the first layer are movable with respect to each other. This encompasses a fixed position of the first layer, the feeder system being movable over and above the whole area of the first layer. Alternatively, the feeder system has a fixed position and the first layer is movable underneath it. In a third alternative both are movable.

When the absorbing polymer material has been applied the first layer is covered with the second layer of permeable fabric and the layers are connected in a connecting pattern. This pattern is designed to form closed areas of desired size and shape, called pockets. These pockets may either enclose desired amounts of absorbing polymer material or be empty. With both empty spaces and empty pockets, pockets not containing absorbing polymer material are denoted. By properly choosing both the distribution of the absorbing polymer material over the first layer and the connecting pattern, the desired cooling capacity will be present in the final garment. When immersed in liquid, preferably water the absorbing polymer material in the pockets will absorb liquid or water forming a (hydro)gel. The empty pockets will separate two or more absorbing polymer material containing pockets, forming areas through which liquid or vapor can escape from the body to the environment.

In the second embodiment described above a liquid—preferably water—soluble material—preferably a polymer—will be present in the absorbing polymer material containing pockets as long as the liquid soluble material is not rinsed out. The presence of the water soluble polymer has appeared to have a stiffening effect to the (hydro)gel formed in the pockets, improving the overall wearing comfort.

Therefore the invention further relates to a cooling garment comprising a first layer of permeable fabric and a second layer of permeable fabric, the first and second layer having been connected together with a connecting pattern, the connecting pattern forming pockets, at least part of the pockets containing absorbing polymer material and a water soluble polymer.

A further advantage of the stiffening effect is that the garment is easily centrifuged. This will result in a hand-dry garment after centrifugation without losing considerable amounts of absorbed liquid, which is ready for use. 

1.-9. (canceled)
 10. Method for the manufacture of cooling parts for a cooling garment comprising the application of an absorbing polymer material to a first layer of a permeable fabric, covering the first layer and the absorbing polymer material with a second layer of a permeable fabric and connecting together the first and the second layer in a connecting pattern, characterized in that the absorbing polymer material is applied in immobilizing form.
 11. Method according to claim 10, wherein the absorbing polymer material is applied as a mixture with a diluent, the mixture having adhesive properties to the first layer.
 12. Method according to claim 10, wherein the absorbing polymer material is applied in bags of a liquid soluble or liquid permeable material.
 13. Method according to claim 12, wherein the absorbing polymer material is applied in bags of a water soluble polymer.
 14. Method according to claim 11, wherein the absorbing polymer material or the mixture is applied in a predetermined pattern
 15. Method according to claim 14, wherein the application of the absorbing polymer material comprises movement of a feeder system for the absorbing polymer material and the first layer with respect to each other.
 16. Cooling parts manufactured by the method according to the invention.
 17. Device, comprising cooling parts according to claim
 16. 18. Device according to claim 17, wherein the device is a cooling garment.
 19. Device, comprising cooling parts comprising a first layer of fabric and a second layer of fabric, the first and second layer having been connected together in a pattern, the pattern forming pockets, the pockets containing absorbing polymer material, characterized in that in addition to the absorbing polymer material the pockets further contain a liquid soluble or liquid permeable material.
 20. Device according to claim 19, wherein the device is a cooling garment.
 21. Device according to claim 19, characterized in that in addition to the absorbing polymer material the pockets further contain a water soluble polymer.
 22. Device according to claim 19 in which at least part of the pockets are separated from each other by areas not containing absorbing polymer material. 